Compellent storage grid is on its way
About this Live Volume thingamyjiggery
Compellent is taking its arrays into grid-based storage for cloud computing. Its fourth generation storage controller and Live Volume "storage hypervisor" deliver the foundation for grid storage arrays deployed within and between data centres for cloud-based computing storage access.
Storage Center 5.4 aggressively increases controller CPU power from the previous dual core 3.0GHz Xeon 5160 design to a dual socket, quad core, Nehalem-class processor, providing eight more powerful cores than the current two, quadrupling controller horsepower, perhaps increasing it sixfold. What is all this extra controller horsepower needed for?
There are six PCI slots available to customers, rather than the five previously available, so an additional Fibre Channel interface card could be plugged in to create more FCAL-linked disk drives. There can be seven drive enclosures per loop. While maintaining support for Fibre Channel and 3Gbit/s SAS disk and solid state drives, Compellent now offers 6Gbit/s SAS drives, with 24 X 2.5-inch drives in a 2U enclosure, each drive having four 6Gbit/s lanes.
There is also support for 3.5-inch 6Gbit/s SAS drives, with 12 in an enclosure, and a new array interface – Fibre Channel over Ethernet (FCoE) – joining 10GbitE iSCSI. One and 2TB 3.5-inch, 7,000rpm, 6Gbit/s SAS drives are supported plus 146GB, 15,000rpm drives, or 10,000rpm drives with either 450GB or 600GB capacity. The 3.5inch drives come in a 3U enclosure holding 16 drives.
Compellent will now provide Cisco CNAs and Nexus switches to link servers to its arrays and take advantage of these protocols. The switch options include Cisco MDS 9148, Nexus 5010 and 5020, MDS 95xx directors supporting 8GBit/s FC, and Brocade TurboIron-24x and Cisco Catalyst 3560-X and 3750-E switches.
The 5.4 controller has a battery-less cache card to cope with power outages and save data.
The new controller can be used by existing Compellent customers with no need for a software licence change. It represents a significant increase in controller processing power and leaves a door wide open to add more functionality.
Product Marketing Director Bob Fine said: "Storage Center 5.4 first in a series of things to come … Live Volume (see below) will make it easier for companies to scale out and move data between systems on demand for dynamic business continuity. Over time, we will continue to make further product enhancements that will allow us to further penetrate the enterprise market. ... we're in the enterprise today and our planned roadmap and investments will continue this progress."
We are rapidly moving into the DS8000/VSP/VMAX area … We'll have additional announcements … There's no need to change our architecture to do this."
Is a traditional dual-controller storage array design capable enough for enterprise use? Gartner Research Director for storage technologies and strategies Valdis Filks said: "Technically yes, multi-controller systems do have a saleability and reliability edge, but not all customers need this level of scale and two controller storage systems are good enough for most users. The usage of multi-core CPUs in today's controllers make the traditional two controller physical storage array virtually a multi-controller storage array. The smarts is in the array O/S or software nowadays."
With Enterprise Manager, Compellent now has a multi-site management tool enabling sysadms to oversee multiple storage arrays in any number of physical locations. They can initiate replication between arrays, access server virtualisation infrastructure and manage any number of Live Volumes between Compellent systems. All the Live Volumes can be managed through a single interface, with Compellent saying this means sysadms can manage multiple data centres in a virtualised grid of [Compellent] storage arrays.
A VMware vSphere 4.1 client plug-in allows VMware users to manage Compellent storage through the vSphere interface. A Storage Adapter for Citrix StorageLink lets sysadms create and recover storage for Microsoft Hyper-V and Citrix XenServer virtual machines. Integration with Citrix StorageLink Site Recovery simplifies the setup and configuration of disaster recovery protection of Hyper-V workloads through integration with Compellent thin provisioning, snapshots and thin replication.
Compellent is also introducing its Live Volume technology with this release, as a software-only upgrade and supporting all Storage Center models and configurations. Live Volume asynchronously replicates a stored volume of data to a second Storage Center array, either in the same datacentre or on the same campus. It is now available on general release after a testing period. Bob Fine said: "We announced our vision for Live Volume 18-20 months ago and provided early code to a small group of customers this spring. We have been continually testing and enhancing it since, based on customer feedback."
Live Volume is analogous to VMware's vMotion and with it an application in a virtual machine can move from one physical server to another (or one virtual server to another) and the storage associated with it – the volume – moves as well, with no loss of storage access. This works with any O/S virtualisation software and aids in hardware migration and planned outages. If this sounds familiar it is probably because it is similar to a capability Brocade offers with its recently-announced VDX switch.
Compellent states Live Volume is a virtualised storage application that provides non-disruptive storage migration between SANs in an integrated environment. Live Volume enables on‑demand volume migration, zero downtime maintenance and disaster avoidance capabilities at a fraction of the price of EMC’s VPLEX, it claims, and requires no hardware, no outages and no system reconfigurations. Different storage volumes can be replicated to different Compellent arrays in a grid-like set-up. The technology is optimised for campus migration "at this time".
Fine said: "Live Volume supports any network connectivity protocol such as 10GbiSCSI, FCoE, iSCSI and FC, and customers can use Live Volume with any tier of storage that is supported by the Storage Center 5.4 hardware as well as previous generations of hardware. It supports any virtualisation environment from VMware, Microsoft, Citrix and Oracle." The marketing manager continued: "Live Volume will make it easier for companies to scale out and move data between systems on demand for dynamic business continuity. Over time, we will continue to make further product enhancements that will allow us to further penetrate the enterprise market."
Live Volume will place an extra processing burden on the controller. Storage consultant Chris Evans said: "With Live Volume, as a LUN is moved, the new target array has to both serve data and move data to the new location. This put significant extra load on the new target. I don't know how many arrays can be in Live Volume, but I would imagine the intention from Compellent would be to have a many to many relationship. If that's the case then I can see a lot of that extra [controller] horsepower being taken up moving data between arrays and handling I/O for non-local data."
The enterprise market: direct or indirect?
The Storage Center 5.4 product seems to have more processing power than it needs and Compellent is making noises about grid storage for the future. Does this mean Compellent is focussing more on the enterprise market?
Stifel Nicolaus analyst Aaron Rakers said: "I believe Compellent will continue to play more into the midrange market than high-end" (eg, against EMC’s Symmetrix, HDS’s VSP, IBM's DS8700, etc). His view is characteristic of one that thinks a direct sales approach, coupled with a strong services offering, is important in enterprise deals.
Compellent uses a 100 per cent indirect sales force with its channel sales focus. Does success in selling to larger enterprises require a direct sales force, the traditional route to getting enterprises to open their wallets? Gartner's Filks offered this thought: "Direct sales forces are always good for vendors but Compellent seems to be doing very well with the indirect channel model. The cost of a direct sales for smaller companies can be an inhibitor to growth as it is very costly to invest and create a world wide direct presence."
Storage blogger Martin Glassborow said: "[Storage Center 5.4] has a very powerful set of features but they'll struggle to get themselves in front of decision makers without a server partnership."
What else could be coming
Compellent's release is full of hints about what else is coming. The new product technology is a "foundation for flexible grid storage … a grid of Compellent arrays acting as one … a grid of shared storage that can be managed and optimised as one." With Live Volume "data is no longer physically bound to a particular array or data centre … [it] can be accessed and shared from multiple locations making Live Volume a key enabler for enterprise scale out and IT clouds."
What else might be coming to use up the new controller's processing power potential? Chris Evans said: "First on my list would be primary de-duplication. This would be (relatively) easy to support on the Compellent array because it already has data in chunks. The ability to have a single physical block of data mapped to multiple logical LUNs already exists with snapshots."
All that's needed is to locate duplicate data within the same tier and remove it. That would require some background scanning process (can't imagine a realtime version would work well). Data would never have to be "inflated" again because new data is written to new blocks, so the trawling process would continually be required (as was used in StorageTek's Iceberg)."
Compellent by the way is increasing its focus on Europe, looking to recruit more channel partners, and intends to hold a version of its annual C-Drive user conference in the UK next May.
A typical Storage Center 5.4 configuration starts at £48,000 (€56,000) and includes clustered Series 40 controllers, software licences Live Volume, Enterprise Manager, Data Progression tiering and Remote Instant Replay replication, and approximately 6TB of tiered 2.5-inch 6Gbit/s SAS storage. Live Volume licences start at under $5,000. In general, Compellent pricing is available from its channel partners and can depend on maintenance and software support options. ®